<messaging> The set of ITU-T communications standards covering electronic
mail services provided by data networks. X.400 was widely used in Europe and
X.400 addresses tend to be much longer than RFC 822 ones. They consist of a set
of bindings for country (c), administrative domain (a), primary management
domain (p), surname (s), given name (g).
For example, the X.400 address,
might be equivalent to RFC 822
X.3 « X3J16 « X3T10 « X.400 » X.409 » X.500 »